Overall slow 2.4 GHz WiFi on OpenWrt devices

Installing and Using OpenWrt
26

With your environment there are several things creating scenarios that might be sapping your bandwidth.

  1. With three virtual APs on each band you are creating extra overhead. Each virtual AP acts like a real AP, the radios have to send extra management frame and deconflict between the virtual APs. Depending on your environment you could be seeing penalties of 10%+ (maybe much more depending on your clients and the below reasons). Good discussion here:
  1. if you have busy clients on the network (ex:torrenting or streaming), lots of clients, any 2.4ghz interference from neighbors / other devices - your device will have to wait more:

https://www.duckware.com/tech/wifi-in-the-us.html#wifispeeds

  1. very few clients truly support 40mhz wide 2.4 channels in real world environments. On the client side they will revert to 20mhz due to all the above two reasons. See here for a quick discussion on the trick that is the 2.4ghz channel:

https://www.duckware.com/tech/wifi-in-the-us.html#wifi4

When doing synthetic benchmarks for wifi turn off your extra virtual APs, quiet down the clients on your network, and pick channels different from any neighbors. Wifi can vary so drastically depending on load and setup that you want something you can replicate. You should be getting rates in the 50mbps range with a 2x2 client 20mhz on 2.4ghz (with a typical PHY of ~72) You should be in the 400mbps range consistently with a 2x2 client 80mhz width on 5ghz.

The 2.4ghz band is terrible and I don’t recommend it for phones. 5ghz is a better place to be. Is it possible to only use two Virtual APs per band or better yet just use the physical interface, no virtuals?

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